In the process of producing a semiconductor device such as IC and LSI, microfabrication by lithography using a photoresist composition has been conventionally performed. Recently, with the increase in integration degree of an integrated circuit, formation of an ultrafine pattern in the sub-micron or quarter-micron region is required. To cope with this requirement, the exposure wavelength also tends to become shorter, for example, from g line to i line or further to KrF excimer laser light. In addition to the excimer laser light, development of lithography using electron beam, X-ray or EUV light is also being pursued at present.
In the photoresist composition, a compound capable of generating an acid upon irradiation with an actinic ray or radiation (hereinafter, sometimes referred to as “acid generator”) is used, and as for the acid generator, a wide variety of compounds have been heretofore proposed. For example, an onium salt-based acid generator such as iodonium salt and sulfonium salt, an oxime sulfonate-based acid generator, a diazomethane-based acid generator, a nitrobenzyl sulfonate-based acid generator, an iminosulfonate-based acid generator, and a disulfone-based acid generator are known (Patent Documents 1 to 3).